Approximately 23 million people worldwide are afflicted with congestive heart failure (“CHF”) and two (2) million new cases of CHF are diagnosed each year worldwide. In contrast to other cardiovascular disorders that have actually declined during the past few decades, the incidence of CHF is currently on the rise. In fact, CHF is one of the most rapidly growing cardiovascular disorders in the United States.
CHF is a chronic inability of the heart to either: a) maintain an adequate output of blood from one or both ventricles of the heart to meet the metabolic demands of the tissues, or; b) adequately circulate blood in one direction through the body, without backflow, (also known as regurgitation).
In a case of CHF, the left ventricle, the right ventricle or both the left and right ventricles generally are weakened such that the volume of blood the heart is able to move may be insufficient for the patient's body. Similarly, if the valves of the heart are leaking (i.e., allowing some blood to regurgitate or flow backwards), fluid may build up behind the heart. With a weakened left ventricle or right ventricle or both, significant problems may occur.
For example, with a weakened left ventricle or right ventricle or both, there is a shift of large volumes of blood from the systemic circulation flow into the pulmonary (lung) circulation flow. If the inability to move the volume of blood forward is due to a left heart side problem (without the right side failing as well), blood continues to be pumped into the lungs by the normal right heart side, while the blood is not pumped adequately out of the lungs by the left heart side. As the volume of blood in the lungs increases, the pulmonary vessels enlarge, pulmonary venous congestion develops, and, once the pulmonary capillary pressure rises above a critical point, fluid begins to filter out of the capillaries into the lung's interstitial spaces and alveoli (air sacs in the lungs where exchange of oxygen and carbon dioxide occurs). Such conditions generally result in pulmonary edema and may subsequently lead to pleural effusion and abdominal effusion.
If the abnormality lies in the right heart side or the pulmonary arteries, this condition limits the ability to move blood forward (i.e., limits the flow of blood to the rest of the body). During this condition, congestion occurs behind the right heart side (causing pleural effusion and/or build-up of fluid in the abdomen). If the left side heart valve allows fluid to regurgitate (flow backwards, upon contraction of the heart), this condition may cause the kidneys and liver to fail, due to fluid build-up therein, and excessive pressure as fluid pressurizes in those organs instead of simply flowing through them. Ultimately, if the patient has a weakened left ventricle or right ventricle or both, the patient will, over time, require a heart transplant and/or will die.
CHF is often caused by a lower non-functioning valve within the heart. CHF also causes valves that may be working properly to stop working properly as the heart increases in size to compensate for its lack of efficiency. As the heart becomes inefficient, the body compensates by increasing the size of the heart which often causes the heart valves to leak. Moreover, as the heart increases in size, the heart grows into the pericardium (which is the sac covering the heart). This condition may cause the pericardium to inflame. At the same time, when the heart expands, it begins to work excessively hard and cannot expand and contract as it needs to. Thus, the expanding heart further makes treatment of CHF difficult.
When treating CHF, drugs are typically given to the patient which cause the patient's heart to beat harder. Alternatively, the drugs cause a thickening or thinning of the blood. While these drugs may help individual patients, they generally do not provide a long-term solution for the patient's heart problems. Accordingly, a second treatment given to the patient may involve invasive surgery, wherein the chest is cut open and a new valve (either artificial or biological) is installed to replace the old (natural) valve, or the natural valve is repaired. A third solution involves a valve replacement similar to the second solution but does so less intrusively by going through smaller holes and performing the surgery endoscopically. The last, and most costly treatment of CHF is a full-blown heart transplant for the patient. Of course, heart transplants are prohibitively expensive and there is currently a shortage of heart donors. After a patient receives a heart transplant, drugs are required to suppress the immune system of the patient to prevent the patient's immune system from attacking the new heart. This presents an entirely new set of potential problems for the transplant patient, with respect to the patient's suppressed immune system.
Because all of the valve replacement solutions require the heart to be cut open, they are very damaging to the heart itself. This means that patients with an extremely weak heart oftentimes cannot survive this type of surgery, even if such a surgery would be otherwise beneficial. If a doctor deems a patient too weak to survive the surgery, the doctor will generally abstain from performing the valve surgery and put a patient on the “waiting list” to receive a heart transplant. Because of the lack of available transplant hearts, and the weakness of the patients awaiting these hearts, many patients die before they have a chance to receive a transplant. Although advances in pharmacology have led to better treatment, 50% of the patients with the most advanced stage of CHF generally die within one year.
U.S. Pat. Nos. 6,719,787 and 6,736,846 both teach heart surgery procedures and devices in which the native heart valve is removed and a new valve is added to the patient. Such procedures still require the patient's heart valves or other valves to be removed and thus involve difficult surgeries.
Heart valve surgery is very intrusive and therefore another solution is needed wherein the heart itself does not have to be cut open. The present embodiments provide this type of solution. More particularly, the present embodiments provide a mechanism whereby a patient who has CHF can have valves placed into veins and arteries that are near the heart but not in the heart itself, which will allow the heart itself to pump more efficiently. This solution may enable many patients with heart disease who would otherwise die or require a heart transplant to be able to have a normal functioning life with a much less intrusive surgery. Furthermore, the present embodiments may prevent a patient who otherwise would need a heart transplant, to never actually need a heart transplant. For these patients, the need for drugs (which may lower the patient's immune system and/or have less desirable other side-effects) may be obviated. Furthermore, because the present embodiments are less intrusive to the heart, it may also be beneficial and an alternative for patients who could not survive the prior art heart valve replacement/repair surgery. Additionally, the present embodiments may be provided endoscopically, and thus the surgery associated with the present embodiments can be minimal.